Systems and methods for purging a chiller system

ABSTRACT

In an embodiment of the present disclosure, a heating, ventilation, and air conditioning (HVAC) system includes a refrigerant loop configured to flow a refrigerant and a purge system configured to purge the HVAC system of non-condensable gases (NCG). The purge system includes a purge heat exchanger configured to receive a mixture of the NCG and the refrigerant. The purge heat exchanger is configured to separate the NCG of the mixture from the refrigerant of the mixture utilizing a chilled fluid. The purge system also includes a thermoelectric assembly configured to remove heat from the chilled fluid.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from and the benefit of U.S.Provisional Application Ser. No. 62/611,412, entitled “SYSTEMS ANDMETHODS FOR PURGING A CHILLER SYSTEM,” filed Dec. 28, 2017, which isherein incorporated by reference in its entirety for all purposes.

BACKGROUND

This application relates generally to purging systems for chillersystems.

Chiller systems, or vapor compression systems, utilize a working fluid,typically referred to as a refrigerant that changes phases betweenvapor, liquid, and combinations thereof in response to being subjectedto different temperatures and pressures associated with operation of thevapor compression system. In low-pressure chiller systems, somecomponents of the low-pressure chiller systems operate at a lowerpressure than the surrounding atmosphere. Due to the pressuredifferential, non-condensable gases (NCG) such as ambient air maymigrate into these low-pressure components, which may causeinefficiencies in the low-pressure chiller system. Accordingly, thelow-pressure chiller system may be purged of the NCG to run moreeffectively. However, traditional purge systems used to remove the NCGmay utilize additional refrigerant with medium or high global warmingpotential (GWP).

SUMMARY

In an embodiment of the present disclosure, a heating, ventilation, andair conditioning (HVAC) system includes a refrigerant loop configured toflow a refrigerant and a purge system configured to purge the HVACsystem of non-condensable gases (NCG). The purge system includes a purgeheat exchanger configured to receive a mixture of the NCG and therefrigerant. The purge heat exchanger is configured to separate the NCGof the mixture from the refrigerant of the mixture utilizing anon-refrigerant fluid. The purge system also includes a thermoelectricassembly configured to remove heat from the non-refrigerant fluid.

In another embodiment of the present disclosure, a heating, ventilation,and air conditioning (HVAC) system includes a refrigerant loop, acompressor disposed along the refrigerant loop and configured tocirculate refrigerant through the refrigerant loop, an evaporatordisposed along the refrigerant loop and configured to place therefrigerant in a heat exchange relationship with a first cooling fluid,a condenser disposed along the refrigerant loop and configured to placethe refrigerant in a heat exchange relationship with a second coolingfluid, and a purge system configured to purge the HVAC system ofnon-condensable gases (NCG). The purge system includes a purge heatexchanger configured to separate a mixture drawn from the condenserutilizing a first refrigerant flow of the refrigerant drawn from theevaporator and utilizing a non-refrigerant fluid. The mixture includesthe NCG and a second refrigerant flow of the refrigerant drawn from thecondenser. The purge heat exchanger is configured to separate the NCG ofthe mixture from the second refrigerant flow of the mixture. The purgesystem also includes thermoelectric assemblies configured to removethermal energy from the first refrigerant flow and the non-refrigerantfluid.

In another embodiment of the present disclosure, a heating, ventilation,and air conditioning (HVAC) system includes a refrigerant loop, acompressor disposed along the refrigerant loop and configured tocirculate refrigerant through the refrigerant loop, an evaporatordisposed along the refrigerant loop and configured to place therefrigerant in a heat exchange relationship with a first cooling fluid,a condenser disposed along the refrigerant loop and configured to placethe refrigerant in a heat exchange relationship with second coolingfluid, and a purge system configured to purge the HVAC system ofnon-condensable gases (NCG). The purge system includes a purge heatexchanger configured to receive a mixture of the NCG and therefrigerant. The purge heat exchanger is configured to separate the NCGof the mixture from the refrigerant of the mixture utilizing a chilledfluid of a chilled fluid loop. The purge system also includes athermoelectric assembly configured to chill the chilled fluid inconjunction with an intermediate fluid of an open fluid loop.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view of an embodiment of a building that mayutilize a heating, ventilation, and air conditioning, (HVAC) system in acommercial setting, in accordance with an aspect of the presentdisclosure;

FIG. 2 is a perspective view of an embodiment of an HVAC system, inaccordance with an aspect of the present disclosure;

FIG. 3 is a schematic of an embodiment of the HVAC system of FIG. 2, inaccordance with an aspect of the present disclosure;

FIG. 4 is a schematic of an embodiment of the HVAC system of FIG. 2, inaccordance with an aspect of the present disclosure;

FIG. 5 is a schematic of a thermoelectric assembly of the HVAC system ofFIG. 2, in accordance with an aspect of the present disclosure;

FIG. 6 is a schematic of a thermoelectric assembly of the HVAC system ofFIG. 2, in accordance with an aspect of the present disclosure.

FIG. 7 is a schematic of an embodiment of the HVAC system of FIG. 2, inaccordance with an aspect of the present disclosure;

FIG. 8 is a schematic of an embodiment of the HVAC system of FIG. 2, inaccordance with an aspect of the present disclosure;

FIG. 9 is a schematic of an embodiment of the HVAC system of FIG. 2, inaccordance with an aspect of the present disclosure;

FIG. 10 is a schematic of an embodiment of the HVAC system of FIG. 2, inaccordance with an aspect of the present disclosure;

FIG. 11 is a schematic of an embodiment of the HVAC system of FIG. 2, inaccordance with an aspect of the present disclosure;

FIG. 12 is a schematic of an embodiment of the HVAC system of FIG. 2, inaccordance with an aspect of the present disclosure;

FIG. 13 is a schematic of an embodiment of the HVAC system of FIG. 2, inaccordance with an aspect of the present disclosure;

FIG. 14 is a schematic of an embodiment of a heat exchanger of the HVACsystem of FIG. 2, in accordance with an aspect of the presentdisclosure; and

FIG. 15 is a schematic of an embodiment of a heat exchanger of the HVACsystem of FIG. 2, in accordance with an aspect of the presentdisclosure.

DETAILED DESCRIPTION

Embodiments of the present disclosure include a purge system that mayimprove an efficiency of purging in a heating, ventilation, and airconditioning (HVAC) system. For example, in certain low-pressure HVACsystems an evaporator may draw in non-condensable gases (NCG) such asambient air from the atmosphere due to a pressure differential betweenthe evaporator and the atmosphere. The NCG may travel through the HVACsystem to ultimately collect within the condenser. These NCG may bedetrimental to the overall performance of the HVAC system, and as such,should be removed. Accordingly, the presently-disclosed embodiments mayefficiently purge the HVAC system of the NCG via the purge system. Forexample, the purge system may pull a mixture of the NCG and refrigerantfrom the condenser. The purge system may then utilize a purge heatexchanger (e.g., a purge coil in a purge chamber) to decrease atemperature of, or remove heat from, the mixture to condense therefrigerant, thereby separating the refrigerant from the NCG due to theincrease in density of the refrigerant as a byproduct of the refrigerantcondensing. Particularly, the purge system may run a chilled fluidthrough the purge coil of the heat exchanger to condense the refrigerantand separate the mixture. In certain embodiments, the chilled fluid maybe chilled via one or more thermoelectric assemblies. Further, incertain embodiments, the chilled fluid may also be chilled via asecondary chilled fluid that was also chilled via thermoelectricassemblies. In some embodiments, the purge heat exchanger may includetwo separate purge coils that may chill the mixture with separatechilled fluids.

Turning now to the drawings, FIG. 1 is a perspective view of anembodiment of an environment for a heating, ventilation, and airconditioning (HVAC) system 10 in a building 12 for a typical commercialsetting. The HVAC system 10 may include a vapor compression system 14that supplies a chilled liquid, which may be used to cool the building12. The HVAC system 10 may also include a boiler 16 to supply warmliquid to heat the building 12 and an air distribution system whichcirculates air through the building 12. The air distribution system canalso include an air return duct 18, an air supply duct 20, and/or an airhandler 22. In some embodiments, the air handler 22 may include a heatexchanger that is connected to the boiler 16 and the vapor compressionsystem 14 by conduits 24. The heat exchanger in the air handler 22 mayreceive either heated liquid from the boiler 16 or chilled liquid fromthe vapor compression system 14, depending on the mode of operation ofthe HVAC system 10. The HVAC system 10 is shown with a separate airhandler on each floor of building 12, but in other embodiments, the HVACsystem 10 may include air handlers 22 and/or other components that maybe shared between or among floors.

FIGS. 2 and 3 are embodiments of the vapor compression system 14 thatcan be used in the HVAC system 10. The vapor compression system 14 maycirculate a refrigerant through a circuit starting with a compressor 32.The circuit may also include a condenser 34, an expansion valve(s) ordevice(s) 36, and a liquid chiller or an evaporator 38. The vaporcompression system 14 may further include a control panel 40 (e.g.,controller) that has an analog to digital (A/D) converter 42, amicroprocessor 44, a non-volatile memory 46, and/or an interface board48.

Some examples of fluids that may be used as refrigerants in the vaporcompression system 14 are hydrofluorocarbon (HFC) based refrigerants,for example, R-410A, R-407, R-134a, hydrofluoro-olefin (HFO), “natural”refrigerants like ammonia (NH₃), R-717, carbon dioxide (CO₂), R-744, orhydrocarbon based refrigerants, water vapor, refrigerants with lowglobal warming potential (GWP), or any other suitable refrigerant. Insome embodiments, the vapor compression system 14 may be configured toefficiently utilize refrigerants having a normal boiling point of about19 degrees Celsius (66 degrees Fahrenheit or less) at one atmosphere ofpressure, also referred to as low pressure refrigerants, versus a mediumpressure refrigerant, such as R-134a. As used herein, “normal boilingpoint” may refer to a boiling point temperature measured at oneatmosphere of pressure.

In some embodiments, the vapor compression system 14 may use one or moreof a variable speed drive (VSDs) 52, a motor 50, the compressor 32, thecondenser 34, the expansion valve or device 36, and/or the evaporator38. The motor 50 may drive the compressor 32 and may be powered by avariable speed drive (VSD) 52. The VSD 52 receives alternating current(AC) power having a particular fixed line voltage and fixed linefrequency from an AC power source, and provides power having a variablevoltage and frequency to the motor 50. In other embodiments, the motor50 may be powered directly from an AC or direct current (DC) powersource. The motor 50 may include any type of electric motor that can bepowered by a VSD or directly from an AC or DC power source, such as aswitched reluctance motor, an induction motor, an electronicallycommutated permanent magnet motor, or another suitable motor.

The compressor 32 compresses a refrigerant vapor and delivers the vaporto the condenser 34 through a discharge passage. In some embodiments,the compressor 32 may be a centrifugal compressor. The refrigerant vaporpumped by the compressor 32 to the condenser 34 may transfer heat to acooling fluid (e.g., water or air) in the condenser 34. The refrigerantvapor may condense to a refrigerant liquid in the condenser 34 as aresult of thermal heat transfer with the cooling fluid. The refrigerantliquid from the condenser 34 may flow through the expansion device 36,for the purposes of reducing the temperature and pressure of therefrigerant liquid, to the evaporator 38. In the illustrated embodimentof FIG. 3, the condenser 34 is water cooled and includes a tube bundle54 connected to a cooling tower 56, which supplies the cooling fluid tothe condenser.

The refrigerant liquid delivered to the evaporator 38 may absorb heatfrom another cooling fluid, which may or may not be the same coolingfluid used in the condenser 34. The refrigerant liquid in the evaporator38 may undergo a phase change from the refrigerant liquid to arefrigerant vapor. As shown in the illustrated embodiment of FIG. 3, theevaporator 38 may include a tube bundle 58 having a supply line 60S anda return line 60R connected to a cooling load 62. The cooling fluid ofthe evaporator 38 (e.g., water, ethylene glycol, calcium chloride brine,sodium chloride brine, or any other suitable fluid) enters theevaporator 38 via return line 60R and exits the evaporator 38 via supplyline 60S. The evaporator 38 may reduce the temperature of the coolingfluid in the tube bundle 58 via thermal heat transfer with therefrigerant. The tube bundle 58 in the evaporator 38 can include aplurality of tubes and/or a plurality of tube bundles. In any case, therefrigerant vapor exits the evaporator 38 and returns to the compressor32 by a suction line to complete the cycle.

FIG. 4 is a schematic of the vapor compression system 14 with anintermediate circuit 64 incorporated between condenser 34 and theexpansion device 36. The intermediate circuit 64 may have an inlet line68 that is directly fluidly connected to the condenser 34. In otherembodiments, the inlet line 68 may be indirectly fluidly coupled to thecondenser 34. As shown in the illustrated embodiment of FIG. 4, theinlet line 68 includes a first expansion device 66 positioned upstreamof an intermediate vessel 70. In some embodiments, the intermediatevessel 70 may be a flash tank (e.g., a flash intercooler). In otherembodiments, the intermediate vessel 70 may be configured as a heatexchanger or a “surface economizer.” In the illustrated embodiment ofFIG. 4, the intermediate vessel 70 is used as a flash tank, and thefirst expansion device 66 is configured to lower the pressure of (e.g.,expand) the refrigerant liquid received from the condenser 34. Duringthe expansion process, a portion of the liquid may vaporize, and thus,the intermediate vessel 70 may be used to separate the vapor from theliquid received from the first expansion device 66. Additionally, theintermediate vessel 70 may provide for further expansion of therefrigerant liquid because of a pressure drop experienced by therefrigerant liquid when entering the intermediate vessel 70 (e.g., dueto a rapid increase in volume experienced when entering the intermediatevessel 70). The vapor in the intermediate vessel 70 may be drawn by thecompressor 32 through a suction line 74 of the compressor 32, or througha centrifugal compressor. In other embodiments, the vapor in theintermediate vessel may be drawn to an intermediate stage of thecompressor 32 (e.g., not the suction stage). The liquid that collects inthe intermediate vessel 70 may be at a lower enthalpy than therefrigerant liquid exiting the condenser 34 because of the expansion inthe expansion device 66 and/or the intermediate vessel 70. The liquidfrom intermediate vessel 70 may then flow in line 72 through a secondexpansion device 36 to the evaporator 38.

In some embodiments, when the vapor compression system 14 is inoperation, the evaporator 38 may function at a pressure that is lowerthan the ambient pressure. As such, NCG may be drawn into the evaporator38 and move through the compressor 32 to gather in the condenser 34.These NCG may cause the vapor compression system 14 to operateinefficiently because the NCG may act as insulators preventing effectiveheat transfer from the refrigerant to the cooling fluid (e.g., water orair) within the condenser 34. Accordingly, the vapor compression system14 may include features to purge the vapor compression system 14 of theNCG.

Particularly, the vapor compression system 14 may include a purge system80 to purge the vapor compression system 14 of NCG. As mentioned above,the purge system 80 may purge the vapor compression system 14 at leastin part by reducing a temperature of, or removing heat from, a mixtureof NCG and refrigerant vapor that is pulled from the condenser 34,thereby condensing the refrigerant vapor and separating the refrigerantfrom the NCG. Specifically, the purge system 80 may remove heat from themixture via a chilled fluid, which may become chilled throughutilization of one or more thermoelectric assemblies 82, as shown inFIGS. 5 and 6. Each thermoelectric assembly 82 may include a set ofconductive plates, such as a hot side 84 and a cold side 86, and athermoelectric device 88, such as a set of semiconductors. Theconductive plates may be coupled to the thermoelectric device 88 viathermal paste. The thermoelectric device 88 may include a set ofextrinsic, doped semiconductors with an electric imbalance, such aspositive (P-type) or negative (N-type) semiconductors, which may carrypositive or negative charges, respectively. For example, heat may beabsorbed through the cold side 86, transferred through thethermoelectric device 88, and released through the hot side 84. Indeed,the thermoelectric assembly 82 may create a temperature difference, or athermal gradient, between the cold side 86 and the hot side 84, from anelectrical energy difference. Further, higher temperature differencesmay decrease the heat removal capability of the thermoelectric assembly82, while smaller temperature differences may increase the heat removalcapability of the thermoelectric assembly 82. Each thermoelectricassembly 82 may utilize a power source 90 to induce an electrical powergradient within the thermoelectric assembly 82. The power source 90 maybe any suitable power source, such as a power grid, a battery, a solarpanel, an electrical generator, a gas engine, the vapor compressionsystem 14, or any combination thereof. The thermoelectric assembly 82may convert the electrical power gradient to a thermal gradient througha thermoelectric effect, or Peltier-Seebeck effect.

The thermoelectric assemblies 82 may utilize the thermal gradient toabsorb heat from fluid 92 flowing and/or disposed within a conduit 94.The cold side 86 of the thermoelectric assembly 82 may be coupled to theconduit 94 via a heat sink 96 and/or heat paste 98, which may conduct,or transfer, heat from the fluid 92 to the thermoelectric device 88,thereby chilling the fluid 92 within the conduit 94. Further, the hotside 84 of the thermoelectric assembly 82 may be coupled to another heatsink 96, which may be configured to remove heat from the hot side 84. Tothis end, the thermoelectric assembly 82 may also include a fan 100configured to draw ambient air 102 in through sides of the heat sink 96and expel heated ambient air 102 to the surroundings. In this manner,the ambient air 102 may remove heat from the heat sink 96 as the fan 100draws the ambient air 102 in through the heat sink 96 and forces theambient air 102 in the form of heated air out of the thermoelectricassembly 82 with an increase in temperature.

As discussed herein, in some embodiments, the hot side 84 of thethermoelectric assembly 82 may additionally, or in the alternative, becoupled to another conduit 94 with another fluid 92, which may also bechilled some amount and configured to remove heat from the hot side 84.In this manner, a temperature of the cold side 86 may be reduced due tothe fact that the hot side 84 may be chilled to some temperature below atemperature of the ambient air 102. Indeed, due at least in part to thereduced temperatures and temperature differential of the cold side 86and the hot side 84, the heat-removal capabilities of the thermoelectricassembly 82 may be increased. Further still, in some embodiments thethermoelectric assembly 82 may include more than one set of the coldside 86, the thermoelectric device 88, and the hot side 84. For example,the conduit 94 may be coupled to a first cold side 86, which is coupledto a first hot side 84 via a first thermoelectric device 88. The firsthot side 84 may additionally be coupled to a second cold side 86, whichis in turn coupled to a second hot side 84 via a second thermoelectricdevice 88. The second hot side 84 may then be coupled to any suitableheat-removing system, such as heat sinks 96, fans 100, and/or conduits94 as discussed above. Indeed, there may be any suitable number of setsof the cold side 86, the thermoelectric device 88, and the hot side 84stacked within the thermoelectric assembly 82.

As illustrated in FIGS. 7-13, the vapor compression system 14 mayinclude the purge system 80, which is configured to remove NCG, such asambient air, from the vapor compression system 14. To this end, thepurge system 80 may include one or more thermoelectric assemblies 82,one or more pumps 110, such as vacuum pumps, liquid pumps, and/orcompressors one or more stop valves 112, and a purge heat exchanger 114.The purge heat exchanger 114 may further include one or more purge coils116 in a purge chamber 118. Further, it should be noted that theconduits discussed in FIGS. 7-13 may be similar to the conduit 94 ofFIGS. 5 and 6.

Further, the vapor compression system 14 may utilize a controller 120 tocontrol certain aspects of operation of the purge system 80. Thecontroller 120 may be any device employing a processor 122 (which mayrepresent one or more processors), such as an application-specificprocessor. The controller 120 may also include a memory device 124 forstoring instructions executable by the processor 122 to perform themethods and control actions described herein for the purge system 80.The processor 122 may include one or more processing devices, and thememory device 124 may include one or more tangible, non-transitory,machine-readable media. By way of example, such machine-readable mediacan include RAM, ROM, EPROM, EEPROM, CD-ROM, or other optical diskstorage, magnetic disk storage or other magnetic storage devices, or anyother medium which can be used to carry or store desired program code inthe form of machine-executable instructions or data structures and whichcan be accessed by the processor 122 or by any general purpose orspecial purpose computer or other machine with a processor.

To this end, the controller 120 may be communicatively coupled to one ormore components of the purge system 80 through a communication system126. In some embodiments, the communication system 126 may communicatethrough a wireless network (e.g., wireless local area networks [WLAN],wireless wide area networks [WWAN], near field communication [NFC]). Insome embodiments, the communication system 126 may communicate through awired network (e.g., local area networks [LAN], wide area networks[WAN]). For example, as shown in FIGS. 7-13, the controller 120 maycommunicate to a number of elements of the purge system 80 such as thepumps 110, the thermoelectric assemblies 82, the stop valves 112, andother components. In some embodiments, functions of the controller 120and the control panel 40 (FIGS. 3 and 4) as described herein may becontrolled through a single controller. In some embodiments, the singlecontroller may be the control panel 40 or the controller 120.

As discussed in further detail below, as chilled fluid flows through thepurge coil 116 of the purge heat exchanger 114, the chilled fluid mayexchange heat with a mixture of refrigerant vapor and NCG that has beenpulled from the condenser 34 or from another part of the system. Asmentioned above, due to the low pressures of the vapor compressionsystem 14 while in operation relative to ambient pressures, the NCG maybe drawn into the evaporator 38 and travel through the vapor compressionsystem 14 to accumulate in the condenser 34. Specifically, the NCG mayaccumulate in one or more portions of the condenser 34. Accordingly, themixture of the NCG and the refrigerant vapor may be pulled from the oneor more portions of the condenser 34. Generally, during normaloperation, one or more portions in which the NCG accumulate may besubstantially below a discharge baffle, near the middle of the condenser34, near an outlet of the condenser 34, near a top of the condenser 34,or any combination thereof.

The NCG that have accumulated in the condenser 34 may be mixed withrefrigerant vapor. The NCG and refrigerant vapor mixture may be drawnthrough a conduit 128 into the purge chamber 118 of the purge heatexchanger 114, which may be due at least in part to a temperature and/orpressure differential created by the chilled fluid passing through thepurge coil 116 of the purge heat exchanger 114. In some embodiments, acompressor 129 may be disposed along the conduit 128. The compressor 129may pump the NCG and refrigerant vapor mixture from the condenser 34into the purge chamber 118 of the purge heat exchanger 114.Particularly, the compressor 129 is configured to increase a pressure ofthe mixture before the mixture enters the purge heat exchanger 114. Inthis manner, the temperature at which the refrigerant vapor of themixture condenses in the purge heat exchanger 114 is increased, therebyreducing a load on the purge system 80.

As the NCG and refrigerant vapor mixture comes into contact with the lowtemperature surface of the purge coil 116, the refrigerant vapor willcondense into refrigerant liquid and create a partial vacuum within thepurge chamber 118 of the purge heat exchanger 114, thereby drawing inmore of the NCG and refrigerant vapor mixture from the condenser 34through the conduit 128. In some embodiments, as mentioned above, theNCG and refrigerant vapor mixture may be drawn through the conduit 128and into the purge heat exchanger 114 due to the compressor 129.Further, as the NCG and refrigerant vapor mixture enters the purge heatexchanger 114 and the refrigerant vapor condenses into refrigerantliquid, the refrigerant liquid will gather in the bottom of the purgeheat exchanger 114. Indeed, due at least partially to a densitydifference between the condensed refrigerant liquid and the NCG, the NCGand other uncondensed refrigerant vapor will collect towards the top ofthe purge heat exchanger 114, while the condensed refrigerant liquidwill collect at the bottom of the purge heat exchanger 114. Accordingly,as more of the refrigerant vapor of the NCG and refrigerant vapormixture condenses within the purge heat exchanger 114, a liquid level ofthe refrigerant liquid within the purge heat exchanger 114 will rise.

Once the liquid level of the refrigerant liquid has reached apredetermined threshold in the purge heat exchanger 114, the refrigerantliquid will be drained through a conduit 130 to the condenser 34, theevaporator 38, or both, and the NCG will be pumped out of the purge heatexchanger 114 by a vacuum pump 132 through a conduit 134. The vacuumpump 132 may then expel the NCG into the atmosphere. In someembodiments, the NCG may be at a high pressure within the purge heatexchanger 114 relative to a pressure of the atmosphere due to thecompressor 129 increasing a pressure of the NCG and refrigerant vapormixture prior to the mixture entering the purge heat exchanger 114.Accordingly, due to the pressure differential between the NCG within thepurge heat exchanger 114 and the atmosphere, the NCG may expelled intothe atmosphere through a stop valve 112 of the conduit 134 without useof the vacuum pump 132.

In some embodiments, the purge heat exchanger 114 may be disposedvertically above the condenser 34 and the evaporator 38. In this manner,the refrigerant liquid may flow to the condenser 34, the evaporator 38,or both, due at least in part to the head pressure differential createdby the height differential of the purge heat exchanger 114 relative tothe condenser 34 and the evaporator 38. In some embodiments, thecondenser 34 may be disposed vertically above the evaporator 38, therebyallowing the refrigerant liquid to flow more easily to the evaporator 38relative to the condenser 34 from the purge heat exchanger 114.

In some embodiments, the purge heat exchanger 114 may include one ormore sensors 138, which may include one or more temperature sensors,pressure sensors, liquid level sensors, ultrasonic sensors, or anycombination thereof. For example, one sensor 138 of the one or moresensors 138 may measure the liquid level of the refrigerant liquidwithin the purge heat exchanger 114 and send data regarding the liquidlevel to the controller 120. If the liquid level is approaching,matching, and/or exceeding the predetermined liquid level threshold, thecontroller 120 may send a signal to one or more of the stop valves 112to allow the refrigerant liquid to drain to the condenser 34, theevaporator 38, or both, as described above. Similarly, the controller120 may send a signal to the pump 132 and/or one or more of the stopvalves 112 to release the NCG through the pump 132 into the atmosphere.

In some embodiments, the controller 120 may determine whether there is asignificant or predetermined amount of NCG within the condenser 34before allowing the NCG and refrigerant vapor mixture to enter the purgeheat exchanger 114, such as by activating one or more of the stop valves112. To determine whether there is a significant or predetermined amountof NCG within the condenser 34, another sensor 138 of the one or moresensors 138 may measure one or more parameters related to a performanceof the vapor compression system 14 and send data indicative of the oneor more parameters to the controller 120 to analyze and process.Specifically, the controller 120 may determine a performance level ofthe vapor compression system 14 based on the one or more parameters. Ifthe controller 120 determines that the performance level of the vaporcompression system 14 is below a predetermined threshold, the controller120 may allow the condenser 34 to be purged as described above byopening an appropriate stop valve 112 and allowing the mixture of NCGand refrigerant vapor to flow to the purge heat exchanger 114 from thecondenser 34. In some embodiments, the controller 120 may purge thecondenser 34 as described above based on a predetermined schedule.

Additionally, or in the alternative, one of the sensors 138 may measurea saturation temperature and an actual temperature within the condenser34 and send data indicative of the saturation and actual temperatures tothe controller 120 to analyze and process. The controller 120 may thendetermine whether the saturation temperature substantially matches theactual temperature. If the saturation temperature does not substantiallymatch the actual temperature, the controller 120 may allow the condenser34 to be purged as described above by opening an appropriate stop valve112 and allowing the mixture of NCG and refrigerant vapor to flow to thepurge heat exchanger 114 from the condenser 34.

As discussed herein, the purge heat exchanger 114 may receive a chilledfluid that flows through the purge coil 116 to condense the refrigerantvapor pulled from the condenser 34. In some embodiments, the purge coil116 may include internal and/or external fins configured to increase arate of heat transfer between the purge coil 116, the fluid within thepurge coil 116, and/or the fluid that is external to the purge coil 116and internal to the purge heat exchanger 114. FIGS. 7-13 depictembodiments of the purge system 80 used to chill the fluid flowingthrough the purge coil 116. For example, as shown in FIG. 7, the purgesystem 80 may include a closed fluid loop 160 configured to chill afluid and flow the chilled fluid through the purge coil 116 to condensethe refrigerant vapor within the purge heat exchanger 114. Particularly,the fluid within closed fluid loop 160 may be a brine and/or awater/glycol mixture with a low freezing point.

The closed fluid loop 160 may utilize a liquid pump 162 to pump thefluid through a conduit 164 and the purge coil 116 of the closed fluidloop 160. Indeed, the liquid pump 162 may be a modified pump that isconfigured to pump brine and/or a water/glycol mixture. Further, asshown in the figure, multiple thermoelectric assemblies 82 may becoupled to the conduit 164 and configured to remove heat from the fluidas it flows through the conduit 164, as described above in reference toFIGS. 5 and 6. There may be any suitable number of thermal electricassemblies 82 coupled to the conduit 164.

In certain embodiments, as shown in FIG. 8, the purge system 80 mayutilize fluid from another source such as the cooling fluid of thecooling load 62 (FIGS. 3 and 4). In other words, the purge system 80 mayutilize fluid from a cooling system of a building, such as the building12 (FIG. 1) through an open fluid loop 165. In certain embodiments, thefluid may be water, brine, or a water/glycol mixture. Particularly, aliquid pump 162 of the open fluid loop 165 may draw fluid from thesupply line 60S through a conduit 166 and supply the fluid to the purgecoil 116 of the purge heat exchanger 114. As the fluid flows through theconduit 166 to the purge coil 116, the fluid may be chilled viathermoelectric assemblies 82 that are coupled to the conduit 166 andconfigured to remove heat from the fluid, as discussed above. In thismanner, the purge coil 116 may receive fluid that has been chilled viathe thermoelectric assemblies 82. As the chilled fluid flows through thepurge coil 116, the refrigerant vapor from the condenser 34 may condensewithin the purge chamber 118. After flowing through the purge coil 116,the fluid may be returned to the supply line 60S. Indeed, the amount offluid drawn from the supply line 60S may be negligible relative to theoverall mass flowrate of the fluid through the supply line 60S. Further,the fluid that is drawn from the supply line 60S and routed to the purgecoil 116 may be at a temperature that is lower than the ambienttemperature due at least in part to the heat exchange process within theevaporator 38 described above. Therefore, the thermoelectric assemblies82 may remove a reduced amount of heat from the fluid of the open fluidloop 165 for the fluid to be at an adequately low temperature tocondense the refrigerant vapor within the purge heat exchanger 114.

In certain embodiments, as shown in FIG. 9, the purge system 80 mayutilize chilled fluid from the closed fluid loop 160 and chilled fluidfrom the open fluid loop 165, which may function similar to embodimentsdiscussed in reference to FIGS. 7 and 8, respectively. Particularly, theclosed fluid loop 160 may utilize the liquid pump 162 to flow the fluidthrough the conduit 168 and through the purge coil 116. As the fluidflows through the conduit 168, the thermoelectric assemblies 82 that arecoupled to the conduit 168 may remove heat from the fluid, therebychilling the fluid. Indeed, the fluid may be a brine, water, and/or awater/glycol mixture. Accordingly, the liquid pump 162 of the closedfluid loop 160 may be a modified pump that is configured to pump water,brine, and/or a water/glycol mixture.

The purge system 80, as shown in the embodiment of FIG. 9, may alsoinclude the open fluid loop 165, which may utilize fluid from thecooling system of a building, such as the building 12 (FIG. 1).Particularly, the liquid pump 162 of the open fluid loop 165 may drawfluid from the supply line 60S and pump the fluid through a conduit 170to the purge coil 116 of the purge heat exchanger 114. As the fluidflows through the conduit 170 to the purge coil 116, thermoelectricassemblies 82 that are coupled to the conduit 170 may remove heat fromthe fluid, thereby further chilling the fluid. In certain embodiments,the fluid drawn from the supply line 60S may be water, brine, or awater/glycol mixture. Accordingly, in such embodiments, the liquid pump162 of the open fluid loop 165 may be configured to pump water, brine,or a water/glycol mixture, respectively.

As discussed above, the closed fluid loop 160 and the open fluid loop165 may flow chilled fluid through the purge coil 116 of the purge heatexchanger 114. Specifically, in certain embodiments, the purge heatexchanger 114 may include two separate purge coils 116, which mayseparately receive chilled fluid from separate fluid loops, such as fromthe closed fluid loop 160 and from the open fluid loop 165, as discussedin further detail below in FIG. 14. Further, as discussed in furtherdetail below, the purge heat exchanger 114 may include a single purgecoil 116 that is configured to receive chilled fluid from separate fluidloops, such as from both the closed fluid loop 160 and the open fluidloop 165, at separate times based on operation of one or more stopvalves 112, as discussed in further detail below in FIG. 15.Additionally, or in the alternative, the purge coil 116 may receive amixture of fluid from separate fluid loops based on operation of one ormore stop valves 112, also as discussed in further detail below in FIG.15. Particularly, the controller 120 may send one or more signals to theappropriate stop valves 112 to control the flow of chilled fluidsthrough the purge heat exchanger 114 as discussed above.

In certain embodiments, as shown in FIG. 10, the purge system 80 mayinclude a refrigerant loop 172 that is configured to flow chilledrefrigerant through the purge coil 116 to condense the vapor refrigerantpulled from the condenser 34. Particularly, a liquid pump 162 of therefrigerant loop 172 that is configured to pump liquid refrigerant maypull liquid refrigerant from the evaporator 48 through a conduit 174. Insome embodiments, the liquid refrigerant pulled from the evaporator 38may include a portion of vapor refrigerant. In other words, the liquidpump 162 may pull a two-phase mixture of vapor refrigerant and liquidrefrigerant from the evaporator 38. Accordingly, in some embodiments,the purge system 80 may include a flash tank, such as the intermediatevessel 70 (FIG. 4), which is disposed along the conduit 174 between theliquid pump 162 and the evaporator 38. To this end, the liquidrefrigerant may be separated from the vapor refrigerant within the flashtank. The liquid refrigerant may be drawn from the flash tank by theliquid pump 162 along the conduit 174, and the vapor refrigerant may berouted from the flash tank to an outlet side of the evaporator 38. Theliquid pump 162 of the refrigerant loop 172 may then pump the liquidrefrigerant through the purge coil 116 and back to the evaporator 38.Before reaching the purge coil 116, the liquid refrigerant may traverseone or more portions of the conduit 174 to which thermoelectricassemblies 82 are coupled. Specifically, the thermoelectric assemblies82 may remove heat from the liquid refrigerant as it flows through theconduit 174, thereby chilling the liquid refrigerant to a subcooledstate. In this manner, the refrigerant may remain in a liquid state asit flows through the purge coil 116, transfers heat to the mixture ofrefrigerant vapor and NCG, and flows back to the evaporator 38. Indeed,the liquid pump 162 of the refrigerant loop 172 may be a modified pumpthat is configured to pump refrigerant liquid.

Further, in certain embodiments, as shown in FIG. 11, the purge system80 may include the refrigerant loop 172 and the open fluid loop 165which may both flow chilled fluid into the purge heat exchanger 114 toseparate the mixture of refrigerant vapor and NCG that is pulled fromthe condenser 34 by condensing refrigerant vapor of the mixture. Indeed,the refrigerant loop 172 may function as described above in reference toFIG. 10, and the open fluid loop 165 may function as described above inreference to FIG. 9. Further, also as discussed above, the refrigerantloop 172 and the open fluid loop 165 may flow chilled fluid throughseparate respective purge coils 116 in certain embodiments, or may flowchilled fluid through a single purge coil 116. Particularly, the purgecoil 116 may receive a mixture of fluid from separate fluid loops basedon operation of one or more stop valves 112 (shown in FIGS. 14 and 15).Specifically, the controller 120 may send one or more signals to theappropriate stop valves 112 to control the flow of chilled fluidsthrough the purge heat exchanger 114.

Further, in all of the embodiments discussed herein, the purge system 80may utilize adsorption chambers 180 to remove NCG from the vaporcompression system 14. For example, as discussed above, the vacuum pump132 may remove gases from the purge chamber 118 of the purge heatexchanger 114. Particularly, in certain embodiments, the vacuum pump 132may remove NCG and refrigerant vapor from the purge chamber 118.Accordingly, the adsorption chambers 180 may remove a portion ofrefrigerant vapor drawn in by the vacuum pump 132 before expelling theNCG into the atmosphere. To illustrate, the vacuum pump 132 may pump themixture of NCG and refrigerant vapor, or “mixture,” through a conduit182 to one or more of the adsorption chambers 180. As the mixturetraverses through one of the adsorption chambers 180, the mixture may bepassed through a modified material 184 of the adsorption chamber 180,and the refrigerant vapor may be adsorbed, or attracted, into and/oronto the modified material 184 due to the properties of the modifiedmaterial 184 and the refrigerant vapor. For example, electrochemicalproperties may aid in adsorption as described herein. Further, as themixture traverses through the adsorption chamber 180, the NCG may not beadsorbed into the modified material 184 also due at least in part to theproperties of the NCG and/or the modified material 184. Accordingly, theNCG may pass through the modified material 184 and continue through anair outlet valve 186 to be expelled into the atmosphere.

As the modified material 184 adsorbs the refrigerant, the modifiedmaterial 184 may eventually become saturated with the refrigerant andmay no longer efficiently adsorb additional refrigerant. Accordingly,heaters 188, such as immersion heaters, outer cable heaters, or bandheaters, may be activated to provide thermal energy to the modifiedmaterial 184 to heat the refrigerant. In this manner, the heaters 188will help the refrigerant overcome the bonds of the modified material184, such that the modified material 184 releases the refrigerant in avapor state. Once released from the modified material 184, therefrigerant vapor may have a high pressure relative to pressures withinthe evaporator 38 such that the refrigerant vapor flows to theevaporator 38 through a conduit 190.

In some embodiments, the stop valves 112 may allow the mixture to flowto only certain adsorption chambers 180 at a time. In this manner, theadsorption chambers 180 may continuously receive and filter the mixtureas described above. For example, the controller 120 may control the stopvalves 112 to allow the mixture to be filtered by one or more specificadsorption chambers 180 of the adsorption chambers 180. Once thespecific adsorption chamber 180 becomes saturated with the refrigerant,the controller 120 may stop flow of the mixture to the specificadsorption chamber 180 and allow the mixture to flow to a differentadsorption chamber 180. Once the controller 120 has stopped flow to thespecific adsorption chamber 180, the controller may activate the heater188 associated with the specific adsorption chamber 180 to allow therefrigerant vapor to flow to the evaporator 38 as described above.Indeed, while the specific adsorption chamber 180 is being heated, thedifferent adsorption chamber 180 may continue to filter the mixture.Once the specific adsorption chamber 180 is sufficiently unsaturatedwith the refrigerant, the controller 120 may once again activate one ormore of the stop valves 112 to allow the mixture to flow the specificadsorption chamber 180. To this end, the purge system 80 may include 1,2, 3, 4, 5, 6, or any other suitable number of individual adsorptionchambers 180 to allow continuous filtration of the mixture.

Further, in certain embodiments, as shown in FIG. 12, the purge system80 may include the closed fluid loop 160 and an open intermediate fluidloop 200, such as an open fluid loop. Particularly, the closed fluidloop 160 may utilize the liquid pump 162 to flow a fluid, which may bewater, brine, or a water/glycol mixture, through a conduit 201 and thepurge coil 116. Indeed, the liquid pump 162 may be a modified pump thatis configured to pump water, brine, or a water/glycol mixture. As theliquid pump 162 pumps the fluid of the closed fluid loop 160 through theconduit 201, a first set of thermoelectric assemblies 82 a may chill thefluid as discussed above. In this manner, as the chilled fluid of theclosed fluid loop 160 flows through the purge coil 116, the chilledfluid may separate the mixture of NCG and refrigerant vapor bycondensing the refrigerant vapor within the purge chamber 118 asdiscussed above.

Further, it should be noted that the cold side 86 of the first set ofthermoelectric assemblies 82 a may be coupled to the conduit 201 whilethe hot side 84 of the first set of thermoelectric assemblies 82 a maybe coupled to a conduit 202 configured to flow another chilled fluid.Specifically, the conduit 202, which is coupled to the hot side 84 ofthe first set of thermoelectric assemblies 82 a, may be part of the openintermediate fluid loop 200.

To illustrate, the liquid pump 162 of the open intermediate fluid loop200 may draw a fluid, which may be water, brine, a water/glycol mixture,or a combination thereof, from the supply line 60S of the cooling load62 (FIGS. 3 and 4) through a conduit 204. Particularly, in certainembodiments, the liquid pump 162 of the open intermediate fluid loop 200may utilize fluid from a cooling system of a building, such as thebuilding 12 (FIG. 1). Indeed, the fluid pumped from the supply line 60Smay be water, brine, or a water/glycol mixture and the liquid pump 162of the open intermediate fluid loop 200 may be configured to pump water,brine, or a water/glycol mixture, respectively. The liquid pump 162 ofthe open intermediate fluid loop 200 may then pump the fluid through aconduit 206, to which a second set of thermoelectric assemblies 82 b maybe coupled. As the fluid of the open intermediate fluid loop 200 passesthrough the conduit 206, the second set of thermoelectric assemblies 82b may remove heat from the fluid. After passing through the conduit 206,the fluid of the open intermediate fluid loop 200 may pass through theconduit 202. Particularly, as mentioned above, the conduit 202 may becoupled to the hot sides 84 of the first set of thermoelectricassemblies 82 a. In this manner, as the fluid passes through the conduit202 of the second set of thermoelectric assemblies 82 b, the fluid mayabsorb some heat from the hot sides 84 of the thermoelectric assemblies82 b.

Indeed, the first set of thermoelectric assemblies 82 a may utilize thechilled fluid flowing through the conduit 202 in place of a fan 100(FIGS. 4 and 5) to increase the capability of the second thermoelectricassemblies 82 a to chill the fluid in the closed fluid loop 160 to alower temperature. For example, the chilled fluid flowing through theconduit 202 may be at a lower temperature than ambient air, which thefan 100 may otherwise utilize to cool the hot side 84. Therefore, byutilizing the chilled fluid within the conduit 202, the temperaturedifference between the cold side 86 and the hot side 84 may be reduced,thereby increasing the heat transfer effectiveness of the purge system80.

After the fluid of the open intermediate fluid loop 200 flows throughthe conduit 202 to cool the hot side 84 of the first set ofthermoelectric assemblies 82 a, the fluid may flow to the return line60R via a conduit 208 to once again be chilled within the evaporator 38as discussed above.

In certain embodiments, as shown in FIG. 13, the purge system 80 mayutilize the refrigerant loop 172 to condense the refrigerant vaporwithin the purge heat exchanger and utilize the intermediate coolingfluid loop 200 to cool the thermoelectric assemblies 82 a that are usedto cool the fluid in the refrigerant loop 172 that is chilling the purgecoil 116. For example, as discussed previously in FIG. 10, the purgesystem 80 may utilize the refrigerant loop 172 to flow refrigerant fromthe evaporator 38 to the purge coil 116 of the purge heat exchanger 114in order to separate the mixture of NCG and refrigerant vapor that ispulled from the condenser 34.

For example, the liquid pump 162 of the refrigerant loop 172 may pumprefrigerant from the evaporator 38 through a conduit 210 and through thepurge coil 116 of the purge heat exchanger 114. Further, as shown, afirst set of thermoelectric assemblies 82 a may be coupled to theconduit 210. Therefore, as the refrigerant flows through the conduit 210to the purge coil 116, the first set of thermoelectric assemblies 82 amay chill, or subcool, the refrigerant. Particularly, the thermoelectricassemblies 82 a may chill the refrigerant such that the refrigerantremains in a liquid state throughout the refrigerant loop 172.

Further, it should be noted that the cold side 86 of the first set ofthermoelectric assemblies 82 a may be coupled to the conduit 210 whilethe hot side 84 of the first set of thermoelectric assemblies 82 a maybe coupled to a conduit 212 configured to flow another chilled fluid.Specifically, the conduit 212, which is coupled to the hot side 84 ofthe first set of thermoelectric assemblies 82 a, may be part of the openintermediate fluid loop 200.

To illustrate, the liquid pump 162 of the open intermediate fluid loop200 may draw a fluid, which may be water, brine, a water/glycol mixture,or a combination thereof, from the supply line 60S of the cooling load62 (FIGS. 3 and 4) through a conduit 214. Particularly, in certainembodiments, the liquid pump 162 of the open intermediate fluid loop 200may utilize fluid from a cooling system of a building, such as thebuilding 12 (FIG. 1). Indeed, the fluid pumped from the supply line 60Smay be water, brine, or a water/glycol mixture and the liquid pump 162of the open intermediate fluid loop 200 may be configured to pump water,brine, or a water/glycol mixture, respectively. The liquid pump 162 ofthe open intermediate fluid loop 200 may then pump the fluid through aconduit 216, to which a second set of thermoelectric assemblies 82 b maybe coupled. As the fluid of the open intermediate fluid loop 200 passesthrough the conduit 216, the second set of thermoelectric assemblies 82b may remove heat from the fluid. After passing through the conduit 216,the fluid of the open intermediate fluid loop 200 may pass through theconduit 212. Particularly, as mentioned above, the conduit 212 may becoupled to the hot sides 84 of the first set of thermoelectricassemblies 82 a. In this manner, as the fluid of the intermediate fluidloop 200 passes through the conduit 212 of the first set ofthermoelectric assemblies 82 a, the fluid may absorb some heat from thehot sides 84 of the first set of thermoelectric assemblies 82 a.

Indeed, the first set of thermoelectric assemblies 82 a may utilize thechilled fluid flowing through the conduit 212 in place of the fan 100(FIGS. 4 and 5) to increase the heat removal capabilities of the secondthermoelectric assemblies 82 a. For example, the chilled fluid flowingthrough the conduit 212 may be at a lower temperature than ambient air,which the fan 100 may otherwise utilize to cool the hot side 84.Therefore, by utilizing the chilled fluid within the conduit 212, thetemperature difference between the cold side 86 and the hot side 84 maybe reduced, thereby increasing the heat transfer effectiveness of thepurge system 80.

After the fluid of the open intermediate fluid loop 200 flows throughthe conduit 212 to cool the hot side 84 of the first set ofthermoelectric assemblies 82 a, the fluid may flow to the return line60R via a conduit 220 to once again be chilled within the evaporator 38as discussed above.

As discussed above, the purge heat exchanger 114 may receive chilledfluid from more than one fluid loop, such as the closed fluid loop 160,the open fluid loop 165, and/or the refrigerant loop 172. Particularly,the heat exchanger 114 may receive chilled fluid from two separate fluidloops. Accordingly, in certain embodiments, as shown in FIG. 14, thepurge heat exchanger 114 may include a first purge coil 116 a, which maybe part of a first fluid loop 222 a, and may also include a second purgecoil 116 b, which may be part of a second fluid loop 222 b. Indeed, incertain embodiments, the first and second fluid loops 222 a, 222 b maybe part of the closed fluid loop 160, the open fluid loop 165, or therefrigerant loop 172. Particularly, in the illustrated embodiment, thefirst purge coil 116 a and the first fluid loop 222 b may be separatefrom the second purge coil 116 b and the second fluid loop 222. In suchembodiments, the controller 120 may operate one or more of the stopvalves 112 to flow chilled fluid through the first fluid loop 222 a, thesecond fluid loop 222 a, or both, through the purge heat exchanger 114.

Further, in certain embodiments, as shown in FIG. 15, the purge heatexchanger 114 may include a single purge coil 116 c, which may receivechilled fluid from the first fluid loop 222 a, the second fluid loop 222b, or both. Indeed, the single purge coil 116 c may be part of the firstfluid loop 222 a, the second fluid loop 222 b, or both. That is, thecontroller 120 may operate the appropriate stop valves 112 to flowchilled fluid from the first fluid loop 222 a, the second fluid loop 222b, or both as a mixture, through the single purge coil 116 c of thepurge heat exchanger 114.

Indeed, as discussed above in reference to FIGS. 14 and 15, the purgeheat exchanger 114 may receive chilled fluid from two separate fluidloops, such as the first fluid loop 222 a and the second fluid loop 222b. In certain embodiments, the first and second fluid loops 222 a, 222 bmay flow different types of fluid. For example, the first fluid loop 222a may utilize water as a chilled fluid while the second fluid loop 222 bmay utilize brine, refrigerant, or a water/glycol mixture. In suchembodiments, the water within the first fluid loop 222 a may have afirst freezing temperature and the brine, refrigerant, or water/glycolmixture within the second fluid loop 222 b may have a second freezingtemperature that is lower than the first freezing temperature.Accordingly, the fluid within the second fluid loop 222 b may be chilledto a lower temperature than the fluid with the first fluid loop 222 abefore the fluids start to solidify, or freeze. Therefore, in certainembodiments, the controller 120 may operate the stop valves 112accordingly to only utilize the chilled fluid in either the first fluidloop 222 a, the second fluid loop 222 b, or both, depending on the typeof chilled fluid and the amount of cooling that may be used tosufficiently condense the refrigerant vapor within the purge heatexchanger 114.

Further, it should be noted that embodiments discussed herein withrespect to FIG. 7-13, specifically the thermoelectric assemblies 82 maybe utilized if the vapor compression system 14 is in operation or if thevapor compression system 14 is not in operation. Yet further, as shownin FIGS. 7-13, in some embodiments, the liquid pumps 162 and/or thevacuum pump 132 may be powered by one or more motors 240, which may beany suitable motor. In some embodiments, the controller 120 may controlthe liquid pump 162 and/or the vacuum pump 132 through communicationwith the one or more motors 240. Particularly, the controller 120 mayoperate the pumps 162, 132 based on temperature and/or pressure dataobtained from the one or more sensors 138 of the purge system 30. Insome embodiments, the one or more motors 240 may receive power from thepower source 90. Moreover, in some embodiments, the controller 120 maycontrol the amount of power sent from the power source 90 to thethermoelectric assemblies 82 to set an appropriate heat removal amount.For example, in some embodiments, the controller 120 may decrease theamount of power sent to the thermoelectric assemblies 82 to save inpower costs or to decrease an amount of heat removal performed by thethermoelectric assemblies 82.

Accordingly, the present disclosure is directed to providing systems andmethods for purging a low-pressure HVAC system (e.g., chiller system,vapor compression system) of NCG that may have entered during operation.Specifically, a purge system may purge the HVAC system of NCG byutilizing a chilled fluid that has been chilled via thermoelectricassemblies. The disclosed embodiments enable the HVAC system to bepurged of the NCG without using additional refrigerant, which may have ahigh GWP. Moreover, it should also be understood that features of any ofthe embodiments discussed herein may be combined with any otherembodiments or features discussed herein.

While only certain features and embodiments have been illustrated anddescribed, many modifications and changes may occur to those skilled inthe art (e.g., variations in sizes, dimensions, structures, shapes andproportions of the various elements, values of parameters (e.g.,temperatures, pressures, etc.), mounting arrangements, use of materials,colors, orientations, etc.) without materially departing from the novelteachings and advantages of the subject matter recited in the claims.The order or sequence of any process or method steps may be varied orre-sequenced according to alternative embodiments. It is, therefore, tobe understood that the appended claims are intended to cover all suchmodifications and changes as fall within the true spirit of theinvention. Furthermore, in an effort to provide a concise description ofthe exemplary embodiments, all features of an actual implementation maynot have been described (i.e., those unrelated to the presentlycontemplated best mode of carrying out the invention, or those unrelatedto enabling the claimed invention). It should be appreciated that in thedevelopment of any such actual implementation, as in any engineering ordesign project, numerous implementation specific decisions may be made.Such a development effort might be complex and time consuming, but wouldnevertheless be a routine undertaking of design, fabrication, andmanufacture for those of ordinary skill having the benefit of thisdisclosure, without undue experimentation.

1. A heating, ventilation, and air conditioning (HVAC) system,comprising: a refrigerant loop configured to flow a refrigerant; and apurge system configured to purge the HVAC system of non-condensablegases (NCG), the purge system comprising: a purge heat exchangerconfigured to receive a mixture comprising the NCG and the refrigerant,wherein the purge heat exchanger is configured to separate the NCG ofthe mixture from the refrigerant of the mixture utilizing anon-refrigerant fluid; and a thermoelectric assembly configured toremove heat from the non-refrigerant fluid.
 2. The HVAC system of claim1, wherein the non-refrigerant fluid comprises water, brine, awater/glycol mixture, or a combination thereof.
 3. The HVAC system ofclaim 1, wherein the purge system comprises a closed fluid loopconfigured to flow the non-refrigerant fluid through a conduit and apurge coil of the purge heat exchanger, and wherein the thermoelectricassembly is coupled to the conduit and configured to remove heat fromthe non-refrigerant fluid as the non-refrigerant fluid flows through theconduit.
 4. The HVAC system of claim 1, comprising: a compressordisposed along the refrigerant loop and configured to circulate therefrigerant through the refrigerant loop; an evaporator disposed alongthe refrigerant loop and configured to place the refrigerant in a heatexchange relationship with a first cooling fluid; and a condenserdisposed along the refrigerant loop and configured to place therefrigerant in a heat exchange relationship with a second cooling fluid.5. The HVAC system of claim 4, wherein the non-refrigerant fluidcomprises a portion of the first cooling fluid, wherein the purge systemcomprises an open fluid loop configured to draw the non-refrigerantfluid from a flow path flowing the first cooling fluid, flow thenon-refrigerant fluid through a conduit and a purge coil of the purgeheat exchanger, and return the non-refrigerant fluid to the flow path,and wherein the thermoelectric assembly is coupled to the conduit and isconfigured to remove heat from the non-refrigerant fluid as thenon-refrigerant fluid flows through the conduit.
 6. The HVAC system ofclaim 4, wherein the non-refrigerant fluid comprises a firstnon-refrigerant fluid and the thermoelectric assembly is a firstthermoelectric assembly, wherein the purge heat exchanger is alsoconfigured to separate the mixture utilizing a second non-refrigerantfluid separate from the first non-refrigerant fluid, and wherein thepurge system comprises a second thermoelectric assembly configured toremove heat from the second non-refrigerant fluid.
 7. The HVAC system ofclaim 6, wherein the purge system comprises a closed fluid loopconfigured to flow the first non-refrigerant fluid through a firstconduit and a purge coil of the purge heat exchanger, wherein the firstthermoelectric assembly is coupled to the first conduit and configuredto remove heat from the first non-refrigerant fluid as the firstnon-refrigerant fluid flows through the first conduit, wherein thesecond non-refrigerant fluid comprises a portion of the first coolingfluid, wherein the purge system comprises an open fluid loop configuredto draw the second non-refrigerant fluid from a flow path flowing thefirst cooling fluid, flow the second non-refrigerant fluid through asecond conduit and the purge coil of the purge heat exchanger, andreturn the second non-refrigerant fluid to the flow path, and whereinthe second thermoelectric assembly is coupled to the second conduit andconfigured to remove heat from the second non-refrigerant fluid as thesecond non-refrigerant fluid flows through the second conduit.
 8. TheHVAC system of claim 7, wherein the purge coil comprises a first purgecoil and a second purge coil, wherein the closed fluid loop comprisesthe first purge coil, and wherein the open fluid loop comprises thesecond purge coil.
 9. The HVAC system of claim 7, wherein the purge coilcomprises a single purge coil, wherein the closed fluid loop comprisesthe single purge coil, and wherein the open fluid loop comprises thesingle purge coil.
 10. The HVAC system of claim 4, comprising a pumpconfigured to draw the mixture from the condenser, increase a pressureof the mixture, and deliver the mixture to the purge heat exchanger. 11.The HVAC system of claim 1, comprising a vacuum pump coupled to thepurge heat exchanger, wherein the vacuum pump is configured to pump gasfrom the purge heat exchanger.
 12. The HVAC system of claim 11, whereinthe vacuum pump is configured to pump the mixture from the purge heatexchanger to an adsorption chamber configured to separate the NCG fromthe refrigerant.
 13. A heating, ventilation, and air conditioning (HVAC)system comprising: a refrigerant loop; a compressor disposed along therefrigerant loop and configured to circulate refrigerant through therefrigerant loop; an evaporator disposed along the refrigerant loop andconfigured to place the refrigerant in a heat exchange relationship witha first cooling fluid; a condenser disposed along the refrigerant loopand configured to place the refrigerant in a heat exchange relationshipwith a second cooling fluid; and a purge system configured to purge theHVAC system of non-condensable gases (NCG), the purge system comprising:a purge heat exchanger configured to separate a mixture drawn from thecondenser utilizing a first refrigerant flow of the refrigerant drawnfrom the evaporator and utilizing a non-refrigerant fluid, wherein themixture comprises the NCG and a second refrigerant flow of therefrigerant drawn from the condenser, and wherein the purge heatexchanger is configured to separate the NCG of the mixture from thesecond refrigerant flow of the mixture; and thermoelectric assembliesconfigured to remove thermal energy from the first refrigerant flow andthe non-refrigerant fluid.
 14. The HVAC system of claim 13, wherein thenon-refrigerant fluid comprises a portion of the first cooling fluid andthe purge system comprises: a purge refrigerant loop configured to flowthe first refrigerant flow and comprising: a first conduit and purgecoils of the purge heat exchanger; and an open fluid loop configured toflow the non-refrigerant fluid and comprising: a second conduit and thepurge coils of the purge heat exchanger.
 15. The HVAC system of claim14, wherein the thermoelectric assemblies comprise a firstthermoelectric assembly and a second thermoelectric assembly, whereinthe first thermoelectric assembly is coupled to the first conduit and isconfigured to remove heat from first refrigerant flow, and wherein thesecond thermoelectric assembly is coupled to the second conduit and isconfigured to remove heat from the non-refrigerant fluid.
 16. The HVACsystem of claim 14, wherein the purge refrigerant loop comprises arefrigerant pump configured to pump the first refrigerant flow throughthe purge refrigerant loop, and wherein the open fluid loop comprises anon-refrigerant liquid pump configured to pump the non-refrigerant fluidthrough the open fluid loop.
 17. The HVAC system of claim 14, whereinthe purge coils comprise a first purge coil and a second purge coil,wherein the purge refrigerant loop comprises the first purge coil, andwherein the open fluid loop comprises the second purge coil.
 18. TheHVAC system of claim 14, wherein the purge coils comprise a single purgecoil, wherein the purge refrigerant loop comprises the single purgecoil, and wherein the open fluid loop comprises the single purge coil.19. The HVAC system of claim 13, wherein the non-refrigerant fluidcomprises water, brine, a water/glycol mixture, or a combinationthereof.
 20. A heating, ventilation, and air conditioning (HVAC) system,comprising: a refrigerant loop; a compressor disposed along therefrigerant loop and configured to circulate refrigerant through therefrigerant loop; an evaporator disposed along the refrigerant loop andconfigured to place the refrigerant in a heat exchange relationship witha first cooling fluid; a condenser disposed along the refrigerant loopand configured to place the refrigerant in a heat exchange relationshipwith a second cooling fluid; and a purge system configured to purge theHVAC system of non-condensable gases (NCG), the purge system comprising:a purge heat exchanger configured to receive a mixture comprising theNCG and the refrigerant, wherein the purge heat exchanger is configuredto separate the NCG of the mixture from the refrigerant of the mixtureutilizing a chilled fluid of a chilled fluid loop; and a thermoelectricassembly configured to chill the chilled fluid in conjunction with anintermediate fluid of an open fluid loop.
 21. The HVAC system of claim20, wherein the thermoelectric assembly is a first thermoelectricassembly, and wherein the purge system comprises a second thermoelectricassembly configured to remove heat from the intermediate fluid of theopen fluid loop.
 22. The HVAC system of claim 20, wherein the chilledfluid loop is a closed fluid loop, and wherein the chilled fluid of thechilled fluid loop is a non-refrigerant fluid.
 23. The HVAC system ofclaim 20, wherein the chilled fluid comprises water, brine, awater/glycol mixture, or a combination thereof.
 24. The HVAC system ofclaim 20, wherein the chilled fluid of the chilled fluid loop comprisesrefrigerant drawn from the evaporator.
 25. The HVAC system of claim 20,wherein the chilled fluid loop comprises a first conduit and a purgecoil of the purge heat exchanger, wherein the open fluid loop comprisesa second conduit, wherein the thermoelectric assembly is coupled to thefirst conduit at a first side of the thermoelectric assembly and iscoupled to the second conduit at a second side of the thermoelectricassembly, wherein the thermoelectric assembly is configured to absorbheat from the chilled fluid via the first side of the thermoelectricassembly, and wherein the intermediate fluid is configured to absorbheat from the second side of the thermoelectric assembly.